User Guide ISDN Terminal Adapter MTA128ST-USB

Chapter 4 - AT Commands, S-Registers, and Result Codes

S-register: S77

Function: V.110 Network Rate Control*

Unit: decimal ASCII code

Range: n=1—use $MB (S76),

n=2—use $MB (S76) or Auto Sync on Answer

Default: 2 (use $MB(S76) or Auto Sync on Answer)

Description: The Network Rate for V.110 will be determined by S76 ($MB). If S77=1,

then the network rate will be set to that of S76 ($MB) and if the network does

not match that of the peer device, then the connection will fail. Properties of

S77=1 apply to both received and originated calls. If the TA will be

answering a V.110 call, then it can be set to auto-synchronize (S77=2) on the

incoming V.110 network rate.

Auto-synchronizing allows the TA to adapt to the client’s network rate without

any need for the host to have its network rate predetermined. If S77=2

and a V.110 call is originated, then the network rate will be that of S76 ($MB).

* The MTA128ST-USB is manufactured in two builds. To determine the build of your terminal

adapter (TA), issue the ATI2 command in a terminal window. If the TA responds to the command

with MTA128ST-USB, then it supports V.110. If your TA resonds to the ATI2 command with

MTA128ST-USB-RC, V.110 support is not available.

S-Register: S80

Function: Persistent DTR Dialing Delay

Unit: 1 second

Range: n=1-255 (1-255 seconds)

Default: 5 (5 seconds)

Description: Once DTR is detected as present (active high) and other conditions required

for the TA to dial are met, a delay of S80 seconds will occur before stored

number 0 is dialed. Some conditions include the TA not being in the

@CONFIG menu, not having a data call present at the time, and Persistent

DTR Dialing must be enabled. By default the TA will delay for 5 seconds

before dialing when all conditions are satisfied.